Regulator for inclosed electrical apparatus



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E. THOMSON REGULATOR FOR INCLOSED ELECTRICAL PPRTUS Filed Oct,- 11, 1925 2 Sheets-Shee 2 Patented Nov. 24, 1925.

UNITED STATES PATENT OE escalier Fien.

ELIHU THOMSON, OF SWAMPSCOTT, MASSACHUSETTS, .ASSIGNOR TO GENERAL ELEC- TRIO COMPANY, A CORPORATION 0F NEW YORK..

REGULATOR INCLOSED ELEGTRECAL APPARATUS.

Application led Uctober 11, 1923.

To all whom t may concern.'

Be it known that I, ELIHU THOMSON, a citizen of the United States, residing at Swanipscott,4 in the county of Essex, State of Massachusetts, have invented certain new and useful Improvements in Regulators for Inclosed Electrical Apparatus, of which the following is a specilication. i

The present invention comprises an electrical apparatus which is inclosed in a sealed receptacle and which is provided with electromagnetic means whereby a desired regulating or controlling eectA is exerted through the wall of the vcontainer from the exterior.

My invention is applicable in particular to the regulation of electron discharge apparatus, such as inclosed X-ray devices For example, in Coolidge and Wagner Patent No. 1,394,144 is described an X-ray apparatus comprising an Xsray tube immersedtogether with a transformer in a body of oil contained in a sealed tank, a ratchet operated rheostat being provided in the tank adjustable through a flexible diaphragm in the wall of the tank. l

In accordance with my present invention I have provided an X-ray outfit in which one member of a regulating outfit is located lixedly within a tank together with the X-ray tube and related parts, and means being provided whereby the electrical charac teristic of this regulating outfit may be inductively varied through the container wall V by an external device thereby avoiding all sealed moving parts which are liable to get out of order. y

My invention is not limited in its ap-l plication to X-ray devices but to any devices'in which a magnetically responsive member is placed within a sealed inclosure and acted upon by another magnetic member located on the outside of the inclosure.

In accordancel with my invention, the magnetic member inside of the sealed receptacle is acted upon by the exterior member through a non-magnetic wall, means be ing provided to vary the inductive relation of the exterior and interior members to produce a desired regulation. For example, in the case of the X-ray apparatus of the type to which reference has been made above, the X-ray cathode contains an inductance coil mounted within the tank and the inductance value of the coil is varied Serial No. 667,952.

by an external regulator which has no physical connection with the inductance coil in the tank, but which is magnetically linked therewith.

In the accompanying drawings, Fig. 1 is a vertical section of an X-ray apparatus as a whole to which my invention is applicable; Fig. 2 is a vertical section of the same showing the mechanical arrangement ofthe coil and core; Figs. 4 and 6 are diagrammatic representations of electrical circuits; Figs. 3, 5, 7 and 8 are detailed views of structural features and modications of my invention.

The X-ray outfit embodying vmy invention shown in Figs. 1 and 4 comprises a tank 1 containing a transformer 2, and an X-ray tube 3 which is connected to thetransformer secondary 4 by the conductors 5, 6. The X-ray tube 3 is provided with a cathode 7 which is capable of being rendered incan-V descent by a current derived from an auxiliary heating transformer 8, connected thereto by the conductors 9, 10.` The X-ray tube is mounted conveniently by insulating supports 11, 11 upon the cover 12. The contained apparatus is immersed in oil as indicated by dashed lines. The tank cover (which may consist of hard rubber or fibre) is bolted to make anoil tight seal. The X-ray tube has been indicated diao'rammatically for the sake of simplicity, but it is to be understood that the X-ray Vtube is of the pure electron type, such as described in Coolidge Patent No. 1,203,495.`

Included in the cathode heatingcircuit is an inductance coil 13 whereby the current in the heating 4circuit and hence the temperature and electron emission of the cathode may be regulated in order to regulate the X-ray output.

As `shown in Fig. 2vthis inductance coil 13 is mounted upon a thin tube 14 of nonmagnetic and preferably high yresistance materia-h as for example, a ynoli-magnetic steel containing 12% or more of manganese or nichrome alloy or any other high resistance met-al which is adaptedto'makea tight joint with the main portion of the receptacle. The core 15 is movable from the exterior into this tube 14, the core being conveniently mounted upon a screw 16 passing through a threaded support 17 which is attached to the main container 1.

In order to avoid eddy `currents in the casing' surrounding the' core a magnetic shunt 19 is provided on the interior of the casing. This shunt may consist ot a set oit thin iron plates mounted upon the tube 11i. Within the casing. As shoivn in 3 these ringshaped plates or washers are split to avoid the induction ot edd);vv currents surrounding the core. When it is desired tc vary the incandescence oit'the cathode 7, thereby varying the current through the .Ti-i. f tube and thus the intensityv ot the X-ray emitted troni the X-ray tube, the core 15 is moved outwardly so as to be Withdrawn it'roni the coil 13,.therebj.v reducing the reactance ot: the cathode circuit 9, and thus increasing the heatingrcurrent in the circuit. Conversely, Whenthe X-ray output is to be reduced, the core 15 is moved inwardly into closer inagnetic. linkage With the coil 13, thereby reducingr the heating current by reason o't the increasee reactance of the cathode circuit.

In some cases the core may have a bipolar shape or iorseshoe s Aape as shown in Fig. 5.

Inthe modiiication of my invention illustrated in Figs. 6., 7, `and 8y both the internal and the external inductive coils 21, 22 are ot the pancake. type. As ydiagran'imatically shown in Fig. ,G the externalcoil 22 .consists ofitwo parallelwvifres or` ribbon conductors which are providedvfh a plurality of taps leading to the` insulated'seements o't a coinmutator 23 numbered consecutively from 1 to l12 as indicated, Brushes 24, 25 are mounted upon fixed resilient supports 26, 27 whereby connection is made to the conductors 28, 29 leadingfto secondary ot a transformer 30. The. primary of this transformer'receives current from the main supply conduct-lors.

The comm-utator 23 and the coil 22 Which consistsrot a double Wound conductor, are fiXedly connected to a hand .vheel 31 and together are connected to a rotatable shatt 32 .which in turn is i'nonntefl on the wall ot the tank as indicated in l By turnii'ip; the coi'nniutator by the hand wheel 3l the effective num-ber et turns ot the coil may be varied 'trom va maxinnnn when ther brushes 24, bear on the sefgjnients l and 7 as shown infFig. (i to a minimuml when the brnsl'ies bear on segments 4 and 10. In the latter case, the-current'divides in opposite directions through the double conductors and thus substantially neutraliz'esy the magnetic e'ttect; Hencetheinductance value oit` the coil is varied accordingly, the tvvo coils 21, 22 being magneti-cally linked'and being traversed by alternating currents substantially in phase. means of the handwheel the coil 22 may berotated from a position giving a maximum boosting-effect tor a high cathode temperatnre thro-ugh aA neutral position to a position giving' al maximum bucking effect for a minimum cathode temperatures.

In somecases,` the Winding 22 may be used asaj short-circuited seconda-ry Without7 eX- ternal excitation. Thishasbeen indicated by the circuit 33 shown in dotted lines. The switch 34C to the transformer 30 is assumed to be open and the switch 35 closed when thus using' the apparatus. In that case When the commutator is in the position shown in 6, the coil ojt' two parallel Wires is shortcuiting, thus termine` closed secondary and increasing the Acurrent in the coil 21 by neutralizing in part its self-induction. IVhen the conm'iutator is turned one-fourth revolution the two halves ot the coil 22 are opposed, and there is no current in the coil. thereby decreasing; the current in the coil 2l.

That I,V claim as new and desire to secure by Letters Patent ot the United States, is Y 1. An. electrical apparatus comprising a sealed tank, an electrical discharge device contained therein and a regulator for said device. having` 'cooperating members, one being;` tixedly located Within said tank and another being located external to saiditank in variable inductive relationship to saidV in"- ternal member. i

2. An electrical apparatus comprising a sealed tank, a' discharge tube locateditherein, having a cathode operable at incandescence, means in said tank 'tor furnishing' a heating current to said cathode, and a circuit external to said tank containing' means for varying the inductance of thel heating` circuit Within said tank. v

3. An X-ray devicevcomprisinga sealed tank, an incandescent cathode X-ray device therein, a heating circuit therefor, and a regulator for said circuit having"l cooperatingV membersone of which is sealed Within said tank, adjacent the non-magnetic Wall11nember, the other being' external thereto and be-y ing inductively related to said internal inember.

4. An X-ray apparatus comprising a tank, anincandescent cathode device therein, means in saidtank itor heatinsr the cathode ot saiddevice, an inductafnce coil in said tank in circuit with said means,l and andindnctive regulator tor said coil located external to said tank and linked by* a magnetic itield with said coil. l

5. An electrical device comprising; a: ren ceptacle 'containing' a Wall section of nonmagrnetic material, coacting inagrnetic'members one ot WhichY is located iixedly Within said container.V on the inner side'fotisaid nonmagnetic section.x and the other beine.f located onithe outside-ot said section, and means: tor varyingrthe magnetic relation ot' saidfmembers., V

6. An; electrical devicecoinprising a. receptacle containing-a Wall member of'nonmagnetic material, coacting magnetic members one-ot which is located tixedlv Within said receptacle on one side of said Wall meme ber;l the` other member being located externally and inmagnetic relation to'said first member, and switching means for varying the effective magnetizin'a' value of said external member.

7. An electrical device comprising a sealed tank, an electrical discharge device contained therein having a cathode operable at incandescence, circuit connections in said tank for furnishing' an alternating current to said cathode, an incluctance coil in said heating l@ circuit, an external inductance coil in inductive relation thereto, a commutator having connections to different sections of said Winding, and means connected in adjustable relation to said commutator for furnishingr an alternating current in phase with said heating current.

In Witness whereof, I have hereunto set my hand this 6th clay of October, 1923.

ELIHU THOMSON. 

